package 树.红黑树;

import 树.TreeNode;

/**
 *
 * 1. 根节点是黑色
 * 2. 叶子节点(指为空的节点NIL)是黑色
 * 3. 一个节点为红色，则它的孩子节点都是黑色
 * 4. 从一个节点开始到深度相同的任意子节点所经过的黑色节点数目相同
 * 5. 满足平衡二叉树性质，即左孩子<根节点<右孩子
 *
 * Created by yang on 2016/9/11.
 */
public class RBTree implements Comparable<TreeNode>{

    // 节点颜色
    public RBTree parents;
    public RBTree lChild;
    public RBTree rChild;
    public String color;
    public int val;

    public RBTree(RBTree parents, RBTree lChild, RBTree rChild, int val, String color) {
        this.parents = parents;
        this.lChild = lChild;
        this.rChild = rChild;
        this.val = val;
        this.color = color;
    }

    /**
     * Compares this object with the specified object for order.  Returns a
     * negative integer, zero, or a positive integer as this object is less
     * than, equal to, or greater than the specified object.
     * <p>
     * <p>The implementor must ensure <tt>sgn(x.compareTo(y)) ==
     * -sgn(y.compareTo(x))</tt> for all <tt>x</tt> and <tt>y</tt>.  (This
     * implies that <tt>x.compareTo(y)</tt> must throw an exception iff
     * <tt>y.compareTo(x)</tt> throws an exception.)
     * <p>
     * <p>The implementor must also ensure that the relation is transitive:
     * <tt>(x.compareTo(y)&gt;0 &amp;&amp; y.compareTo(z)&gt;0)</tt> implies
     * <tt>x.compareTo(z)&gt;0</tt>.
     * <p>
     * <p>Finally, the implementor must ensure that <tt>x.compareTo(y)==0</tt>
     * implies that <tt>sgn(x.compareTo(z)) == sgn(y.compareTo(z))</tt>, for
     * all <tt>z</tt>.
     * <p>
     * <p>It is strongly recommended, but <i>not</i> strictly required that
     * <tt>(x.compareTo(y)==0) == (x.equals(y))</tt>.  Generally speaking, any
     * class that implements the <tt>Comparable</tt> interface and violates
     * this condition should clearly indicate this fact.  The recommended
     * language is "Note: this class has a natural ordering that is
     * inconsistent with equals."
     * <p>
     * <p>In the foregoing description, the notation
     * <tt>sgn(</tt><i>expression</i><tt>)</tt> designates the mathematical
     * <i>signum</i> function, which is defined to return one of <tt>-1</tt>,
     * <tt>0</tt>, or <tt>1</tt> according to whether the value of
     * <i>expression</i> is negative, zero or positive.
     *
     * @param o the object to be compared.
     * @return a negative integer, zero, or a positive integer as this object
     * is less than, equal to, or greater than the specified object.
     * @throws NullPointerException if the specified object is null
     * @throws ClassCastException   if the specified object's type prevents it
     *                              from being compared to this object.
     */
    @Override
    public int compareTo(TreeNode o) {

        return this.val - o.val;
    }
}
